insque.c

来自「Algorithms for Image Processing and Comp」· C语言 代码 · 共 50 行

/* This is file INSQUE.C */
/* This file may have been modified by DJ Delorie (Jan 1991).  If so,
** these modifications are Coyright (C) 1993 DJ Delorie, 24 Kirsten Ave,
** Rochester NH, 03867-2954, USA.
*/

/*
 * Copyright (c) 1987 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)insque.c	5.3 (Berkeley) 6/1/90";
#endif /* LIBC_SCCS and not lint */

/*
 * insque -- vax insque instruction
 *
 * NOTE: this implementation is non-atomic!!
 */

struct vaxque {		/* queue format expected by VAX queue instructions */
	struct vaxque	*vq_next;
	struct vaxque	*vq_prev;
};

void
insque(e, prev)
	register struct vaxque *e, *prev;
{
	e->vq_prev = prev;
	e->vq_next = prev->vq_next;
	prev->vq_next->vq_prev = e;
	prev->vq_next = e;
}